Given the set X and Y of a circle/ellipse how would you calculate the diameter?

Mapping polar coordinates to cartesian coordinates

theta = linspace(0, 2*pi, 15000);
[x,y] = pol2cart(theta, rho);

How would I calculate the diameter? I thought about calculating the circumference and then I could use this formula C/pi = d but I am not sure how to do this. If it is an ellipse (almost circle like) then I want to approximate the diameter by treating the ellipse as a circle. How would I do this if I have the set x and y describing these areas?

Answer 1

[Sam Chak]

hi @Glypton

One way is to fit the data (x, y) using the circle equation model.

From the fitted model, you will know the radius, r, and then you estimate the diameter, .

Does it sound easy enough? I wonder.